ITR/ASE-SIM: Multiscale Treatment of Systems with Strong Heterogeneities: Development of Hybrid Atomistic-Coarse-Grained Methodology and Computer Code

内布拉斯加大学的Xiao Zeng，Dennis Diestler和Ruqiang Feng得到了信息技术研究计划化学部的支持，以开发一种能够描述多尺度过程的混合原子粗粒度计算方法。 德保罗大学的鲁本·帕拉也将作为暑期访问学者参加。 原型系统由两个平面固体基板分离的界面处的流体膜。 在界面附近，原子可以执行不规则的，大幅度的运动，而远区域的基板均匀应变。 流体和近区被原子化处理，而远区被描述为一个粗粒网格的连续介质力学。 热机械性能计算系综平均，这是由Monte Carlo模拟的影响。本研究的预期成果是一个强大的计算技术，用于分析现实的流体-固体和固体-固体界面系统的热机械响应，其中的分子非均匀界面的宏观连续耦合起着至关重要的作用。 虽然具体的配方将铸造与薄膜润滑和纳米压痕的背景下，该方法是适用于其他现实世界的物理问题，如裂纹扩展。

Xiao Zeng, Dennis Diestler, and Ruqiang Feng of the University of Nebraska are supported by the Chemistry Division under the Information Technology Research program to develop a hybrid atomistic-coarse-grained computational methodology capable of describing multi-scale processes. Ruben Parra of DePaul University will also participate as a summer visiting scholar. The prototypical system consists of two planar solid substrates separated at the interface by a fluid film. In the vicinity of the interface, atoms can execute irregular, large-amplitude motions whereas far regions of the substrates are homogenously strained. The fluid and near regions are treated atomistically while the far regions are described by continuum mechanics as a coarse-grain mesh. Thermomechanical properties are computed at ensemble averages, which are effected by Monte Carlo simulation. The expected outcome of this research is a powerful computational technique for analyzing the thermomechanical response of realistic fluid-solid and solid-solid interfacial systems, in which the coupling of the molecularly heterogeneous interface to the macroscopic continuum plays as essential role. Although the specific formulations will be cast with the contexts of thin-film lubrication and nanoindentation, the approach is applicable to other real-world physical problems such as crack propagation.